housing_prices = read.csv("C:/Users/25047390/OneDrive - UTS/Desktop/module 10/Housing_prices.csv")

Observations

housing_prices
##      ID river  rooms price   age industry ptratio low_ses
## 1     1    No 6-room  21.6  78.9     7.07    17.8    9.14
## 2     2    No 7-room  34.7  61.1     7.07    17.8    4.03
## 3     3    No 7-room  33.4  45.8     2.18    18.7    2.94
## 4     4    No 7-room  36.2  54.2     2.18    18.7    5.33
## 5     5    No 6-room  28.7  58.7     2.18    18.7    5.21
## 6     6    No 6-room  20.4  61.8     8.14    21.0    8.26
## 7     7    No 6-room  18.2  84.5     8.14    21.0   10.26
## 8     8    No 6-room  19.9  56.5     8.14    21.0    8.47
## 9     9    No 6-room  23.1  29.3     8.14    21.0    6.58
## 10   10    No 6-room  17.5  81.7     8.14    21.0   14.67
## 11   11    No 5-room  20.2  36.6     8.14    21.0   11.69
## 12   12    No 6-room  18.2  69.5     8.14    21.0   11.28
## 13   13    No 6-room  13.6  98.1     8.14    21.0   21.02
## 14   14    No 6-room  19.6  89.2     8.14    21.0   13.83
## 15   15    No 6-room  15.2  91.7     8.14    21.0   18.72
## 16   16    No 6-room  14.5 100.0     8.14    21.0   19.88
## 17   17    No 6-room  15.6  94.1     8.14    21.0   16.30
## 18   18    No 6-room  13.9  85.7     8.14    21.0   16.51
## 19   19    No 6-room  16.6  90.3     8.14    21.0   14.81
## 20   20    No 6-room  14.8  88.8     8.14    21.0   17.28
## 21   21    No 6-room  18.4  94.4     8.14    21.0   12.80
## 22   22    No 7-room  21.0  87.3     8.14    21.0   11.98
## 23   23    No 6-room  12.7  94.1     8.14    21.0   22.60
## 24   24    No 6-room  14.5 100.0     8.14    21.0   13.04
## 25   25    No 6-room  13.2  82.0     8.14    21.0   27.71
## 26   26    No 6-room  13.1  95.0     8.14    21.0   18.35
## 27   27    No 6-room  13.5  96.9     8.14    21.0   20.34
## 28   28    No 6-room  18.9  68.2     5.96    19.2    9.68
## 29   29    No 6-room  20.0  61.4     5.96    19.2   11.41
## 30   30    No 6-room  21.0  41.5     5.96    19.2    8.77
## 31   31    No 6-room  24.7  30.2     5.96    19.2   10.13
## 32   32    No 7-room  26.6   2.9     6.91    17.9    4.84
## 33   33    No 6-room  25.3   6.6     6.91    17.9    5.81
## 34   34    No 6-room  24.7   6.5     6.91    17.9    7.44
## 35   35    No 6-room  21.2  40.0     6.91    17.9    9.55
## 36   36    No 6-room  19.3  33.8     6.91    17.9   10.21
## 37   37    No 6-room  20.0  33.3     6.91    17.9   14.15
## 38   38    No 6-room  16.6  85.5     6.91    17.9   18.80
## 39   39    No 5-room  14.4  95.3     6.91    17.9   30.81
## 40   40    No 6-room  19.4  62.0     6.91    17.9   16.20
## 41   41    No 6-room  24.2   6.6    10.81    19.2    6.72
## 42   42    No 6-room  21.7  17.5    10.81    19.2    9.88
## 43   43    No 6-room  22.8   7.8    10.81    19.2    5.52
## 44   44    No 6-room  23.4   6.2    10.81    19.2    7.54
## 45   45    No 6-room  24.1   6.0    12.83    18.7    6.78
## 46   46    No 6-room  21.4  45.0    12.83    18.7    8.94
## 47   47    No 6-room  20.0  74.5    12.83    18.7   11.97
## 48   48    No 6-room  20.8  45.8    12.83    18.7   10.27
## 49   49    No 6-room  21.2  53.7    12.83    18.7   12.34
## 50   50    No 6-room  20.3  36.6    12.83    18.7    9.10
## 51   51    No 6-room  23.9  48.0     4.49    18.5    9.62
## 52   52    No 7-room  26.6  56.1     4.49    18.5    6.53
## 53   53    No 6-room  22.5  45.1     4.49    18.5   12.86
## 54   54    No 6-room  22.2  56.8     4.49    18.5    8.44
## 55   55    No 7-room  23.6  86.3     3.41    17.8    5.50
## 56   56    No 7-room  28.7  63.1     3.41    17.8    5.70
## 57   57    No 6-room  22.6  66.1     3.41    17.8    8.81
## 58   58    No 6-room  22.0  73.9     3.41    17.8    8.20
## 59   59    No 7-room  28.4  57.8     2.89    18.0    6.65
## 60   60    No 6-room  21.4  69.6     2.89    18.0   11.34
## 61   61    No 7-room  38.7  76.0     2.89    18.0    4.21
## 62   62    No 7-room  43.8  36.9     2.89    18.0    3.57
## 63   63    No 7-room  33.2  62.5     2.89    18.0    6.19
## 64   64    No 7-room  27.5  79.9     8.56    20.9    9.42
## 65   65    No 7-room  26.5  71.3     8.56    20.9    7.67
## 66   66    No 6-room  18.6  85.4     8.56    20.9   10.63
## 67   67    No 6-room  19.3  87.4     8.56    20.9   13.44
## 68   68    No 6-room  20.1  90.0     8.56    20.9   12.33
## 69   69    No 6-room  19.5  96.7     8.56    20.9   16.47
## 70   70    No 6-room  19.5  91.9     8.56    20.9   18.66
## 71   71    No 6-room  20.4  85.2     8.56    20.9   14.09
## 72   72    No 6-room  19.8  97.1     8.56    20.9   12.27
## 73   73    No 6-room  19.4  91.2     8.56    20.9   15.55
## 74   74    No 6-room  21.7  54.4     8.56    20.9   13.00
## 75   75    No 7-room  22.8  81.6    10.01    17.8   10.16
## 76   76    No 6-room  18.8  92.9    10.01    17.8   16.21
## 77   77    No 6-room  18.7  95.4    10.01    17.8   17.09
## 78   78    No 6-room  18.5  84.2    10.01    17.8   10.45
## 79   79    No 6-room  18.3  88.2    10.01    17.8   15.76
## 80   80    No 6-room  21.2  72.5    10.01    17.8   12.04
## 81   81    No 6-room  19.2  82.6    10.01    17.8   10.30
## 82   82    No 6-room  20.4  73.1    10.01    17.8   15.37
## 83   83    No 6-room  19.3  65.2    10.01    17.8   13.61
## 84   84    No 6-room  22.0  69.7    25.65    19.1   14.37
## 85   85    No 6-room  20.3  84.1    25.65    19.1   14.27
## 86   86    No 6-room  20.5  92.9    25.65    19.1   17.93
## 87   87    No 6-room  17.3  97.0    25.65    19.1   25.41
## 88   88    No 6-room  18.8  95.8    25.65    19.1   17.58
## 89   89    No 6-room  21.4  88.4    25.65    19.1   14.81
## 90   90    No 6-room  15.7  95.6    25.65    19.1   27.26
## 91   91    No 6-room  16.2  96.0    21.89    21.2   17.19
## 92   92    No 6-room  18.0  98.8    21.89    21.2   15.39
## 93   93    No 6-room  14.3  94.7    21.89    21.2   18.34
## 94   94    No 6-room  19.2  98.9    21.89    21.2   12.60
## 95   95    No 6-room  19.6  97.7    21.89    21.2   12.26
## 96   96    No 6-room  23.0  97.9    21.89    21.2   11.12
## 97   97    No 6-room  18.4  95.4    21.89    21.2   15.03
## 98   98    No 6-room  15.6  98.4    21.89    21.2   17.31
## 99   99    No 6-room  18.1  98.2    21.89    21.2   16.96
## 100 100    No 6-room  17.4  93.5    21.89    21.2   16.90
## 101 101    No 6-room  17.1  98.4    21.89    21.2   14.59
## 102 102    No 6-room  13.3  98.2    21.89    21.2   21.32
## 103 103    No 6-room  17.8  97.9    21.89    21.2   18.46
## 104 104    No 6-room  14.0  93.6    21.89    21.2   24.16
## 105 105    No 5-room  14.4 100.0    21.89    21.2   34.41
## 106 106   Yes 5-room  13.4 100.0    19.58    14.7   26.82
## 107 107    No 5-room  15.6 100.0    19.58    14.7   26.42
## 108 108    No 4-room  11.8  97.8    19.58    14.7   29.29
## 109 109    No 6-room  13.8 100.0    19.58    14.7   27.80
## 110 110    No 6-room  15.6 100.0    19.58    14.7   16.65
## 111 111    No 4-room  14.6  95.7    19.58    14.7   29.53
## 112 112    No 5-room  17.8  93.8    19.58    14.7   28.32
## 113 113    No 6-room  15.4  94.9    19.58    14.7   21.45
## 114 114    No 6-room  21.5  97.3    19.58    14.7   14.10
## 115 115    No 5-room  19.6 100.0    19.58    14.7   13.28
## 116 116   Yes 5-room  15.3  88.0    19.58    14.7   12.12
## 117 117    No 6-room  19.4  98.5    19.58    14.7   15.79
## 118 118   Yes 6-room  17.0  96.0    19.58    14.7   15.12
## 119 119   Yes 6-room  15.6  82.6    19.58    14.7   15.02
## 120 120    No 5-room  13.1  94.0    19.58    14.7   16.14
## 121 121    No 7-room  41.3  97.4    19.58    14.7    4.59
## 122 122    No 6-room  24.3 100.0    19.58    14.7    6.43
## 123 123    No 7-room  23.3 100.0    19.58    14.7    7.39
## 124 124   Yes 6-room  27.0  92.6    19.58    14.7    5.50
## 125 125    No 7-room  50.0  90.8    19.58    14.7    1.73
## 126 126   Yes 7-room  50.0  98.2    19.58    14.7    1.92
## 127 127   Yes 7-room  50.0  93.9    19.58    14.7    3.32
## 128 128    No 6-room  22.7  91.8    19.58    14.7   11.64
## 129 129    No 6-room  25.0  93.0    19.58    14.7    9.81
## 130 130    No 7-room  50.0  96.2    19.58    14.7    3.70
## 131 131    No 6-room  23.8  79.2    19.58    14.7   12.14
## 132 132    No 6-room  23.8  96.1    19.58    14.7   11.10
## 133 133    No 6-room  22.3  95.2    19.58    14.7   11.32
## 134 134    No 6-room  17.4  94.6    19.58    14.7   14.43
## 135 135    No 6-room  19.1  97.3    19.58    14.7   12.03
## 136 136    No 6-room  23.1  88.5     4.05    16.6   14.69
## 137 137    No 6-room  23.6  84.1     4.05    16.6    9.04
## 138 138    No 6-room  22.6  68.7     4.05    16.6    9.64
## 139 139    No 7-room  29.4  33.1     4.05    16.6    5.33
## 140 140    No 6-room  23.2  47.2     4.05    16.6   10.11
## 141 141    No 6-room  24.6  73.4     4.05    16.6    6.29
## 142 142    No 7-room  29.9  74.4     4.05    16.6    6.92
## 143 143    No 7-room  37.2  58.4     2.46    17.8    5.04
## 144 144    No 7-room  39.8  83.3     2.46    17.8    7.56
## 145 145    No 6-room  36.2  62.2     2.46    17.8    9.45
## 146 146    No 7-room  37.9  92.2     2.46    17.8    4.82
## 147 147    No 7-room  32.5  95.6     2.46    17.8    5.68
## 148 148    No 6-room  26.4  89.8     2.46    17.8   13.98
## 149 149    No 6-room  29.6  68.8     2.46    17.8   13.15
## 150 150    No 7-room  50.0  53.6     2.46    17.8    4.45
## 151 151    No 6-room  22.6  22.3    10.59    18.6   10.87
## 152 152    No 6-room  24.4  52.5    10.59    18.6   10.97
## 153 153    No 6-room  22.5  72.7    10.59    18.6   18.06
## 154 154   Yes 6-room  24.4  59.1    10.59    18.6   14.66
## 155 155   Yes 5-room  20.0 100.0    10.59    18.6   23.09
## 156 156   Yes 6-room  21.7  92.1    10.59    18.6   17.27
## 157 157   Yes 5-room  19.3  88.6    10.59    18.6   23.98
## 158 158   Yes 6-room  22.4  53.8    10.59    18.6   16.03
## 159 159    No 6-room  28.1  32.3    10.59    18.6    9.38
## 160 160    No 5-room  23.7   9.8    10.59    18.6   29.55
## 161 161    No 6-room  25.0  42.4    10.59    18.6    9.47
## 162 162   Yes 6-room  23.3  56.0    13.89    16.4   13.51
## 163 163    No 7-room  28.7  85.1    13.89    16.4    9.69
## 164 164   Yes 6-room  21.5  93.8    13.89    16.4   17.92
## 165 165   Yes 6-room  23.0  92.4    13.89    16.4   10.50
## 166 166   Yes 7-room  26.7  88.5     6.20    17.4    9.71
## 167 167   Yes 6-room  21.7  91.3     6.20    17.4   21.46
## 168 168   Yes 7-room  27.5  77.7     6.20    17.4    9.93
## 169 169    No 7-room  30.1  80.8     6.20    17.4    7.60
## 170 170    No 7-room  44.8  78.3     6.20    17.4    4.14
## 171 171    No 7-room  50.0  83.0     6.20    17.4    4.63
## 172 172    No 7-room  37.6  86.5     6.20    17.4    3.13
## 173 173    No 7-room  31.6  79.9     6.20    17.4    6.36
## 174 174    No 7-room  46.7  17.0     6.20    17.4    3.92
## 175 175    No 7-room  31.5  21.4     6.20    17.4    3.76
## 176 176    No 6-room  24.3  68.1     6.20    17.4   11.65
## 177 177    No 7-room  31.7  76.9     6.20    17.4    5.25
## 178 178    No 7-room  41.7  73.3     6.20    17.4    2.47
## 179 179    No 7-room  48.3  70.4     6.20    17.4    3.95
## 180 180   Yes 7-room  29.0  66.5     6.20    17.4    8.05
## 181 181    No 6-room  24.0  61.5     6.20    17.4   10.88
## 182 182   Yes 7-room  25.1  76.5     6.20    17.4    9.54
## 183 183    No 7-room  31.5  71.6     6.20    17.4    4.73
## 184 184    No 6-room  23.9  18.4    13.92    16.0    8.58
## 185 185    No 6-room  21.7  42.3    13.92    16.0   10.40
## 186 186    No 7-room  28.6  31.1    13.92    16.0    6.27
## 187 187    No 7-room  27.1  51.0    13.92    16.0    7.39
## 188 188    No 6-room  20.3  58.0    13.92    16.0   15.84
## 189 189    No 7-room  22.8  82.5     9.90    18.4    4.54
## 190 190    No 6-room  20.3  76.7     9.90    18.4    9.97
## 191 191    No 4-room  16.1  37.8     9.90    18.4   12.64
## 192 192    No 6-room  22.1  52.8     9.90    18.4    5.98
## 193 193    No 6-room  19.4  90.4     9.90    18.4   11.72
## 194 194    No 6-room  21.6  82.8     9.90    18.4    7.90
## 195 195    No 7-room  23.8  87.3     9.90    18.4    9.28
## 196 196    No 6-room  16.2  77.7     9.90    18.4   11.50
## 197 197    No 6-room  17.8  83.2     9.90    18.4   18.33
## 198 198    No 6-room  19.8  71.7     9.90    18.4   15.94
## 199 199    No 6-room  23.1  67.2     9.90    18.4   10.36
## 200 200    No 6-room  21.0  58.8     9.90    18.4   12.73
## 201 201    No 6-room  23.8  52.3     7.38    19.6    7.20
## 202 202    No 6-room  23.1  54.3     7.38    19.6    6.87
## 203 203    No 6-room  20.4  49.9     7.38    19.6    7.70
## 204 204    No 6-room  18.5  74.3     7.38    19.6   11.74
## 205 205    No 6-room  25.0  40.1     7.38    19.6    6.12
## 206 206    No 6-room  24.6  14.7     7.38    19.6    5.08
## 207 207    No 6-room  23.0  28.9     7.38    19.6    6.15
## 208 208    No 6-room  22.2  43.7     7.38    19.6   12.79
## 209 209    No 6-room  19.3  25.8     3.24    16.9    9.97
## 210 210    No 6-room  22.6  17.2     3.24    16.9    7.34
## 211 211    No 6-room  19.8  32.2     3.24    16.9    9.09
## 212 212    No 6-room  22.2  38.1     5.19    20.2    5.68
## 213 213    No 6-room  20.7  38.5     5.19    20.2    6.75
## 214 214    No 6-room  21.1  34.5     5.19    20.2    8.01
## 215 215    No 6-room  19.5  46.3     5.19    20.2    9.80
## 216 216    No 6-room  18.5  59.6     5.19    20.2   10.56
## 217 217    No 6-room  20.6  37.3     5.19    20.2    8.51
## 218 218    No 6-room  19.0  45.4     5.19    20.2    9.74
## 219 219    No 6-room  18.7  58.5     5.19    20.2    9.29
## 220 220    No 7-room  16.5  59.7     1.89    15.9    8.65
## 221 221    No 6-room  17.5  48.5     4.39    18.8   10.53
## 222 222    No 6-room  17.2  52.3     4.39    18.8   12.67
## 223 223   Yes 6-room  17.8  97.4    18.10    20.2   17.60
## 224 224   Yes 6-room  21.7  91.0    18.10    20.2   13.27
## 225 225   Yes 6-room  22.7  83.4    18.10    20.2   11.48
## 226 226    No 6-room  22.6  81.3    18.10    20.2   12.67
## 227 227    No 6-room  25.0  88.0    18.10    20.2    7.79
## 228 228    No 6-room  19.9  91.1    18.10    20.2   14.19
## 229 229    No 5-room  20.8  96.2    18.10    20.2   10.19
## 230 230   Yes 6-room  16.8  89.0    18.10    20.2   14.64
## 231 231   Yes 7-room  21.9  82.9    18.10    20.2    5.29
## 232 232    No 4-room  27.5  87.9    18.10    20.2    7.12
## 233 233    No 4-room  21.9  91.4    18.10    20.2   14.00
## 234 234    No 4-room  23.1 100.0    18.10    20.2   13.33
## 235 235    No 4-room  50.0 100.0    18.10    20.2    3.26
## 236 236   Yes 7-room  50.0  96.8    18.10    20.2    3.73
## 237 237   Yes 7-room  50.0  97.5    18.10    20.2    2.96
## 238 238    No 6-room  50.0 100.0    18.10    20.2    9.53
## 239 239   Yes 6-room  50.0  89.6    18.10    20.2    8.88
## 240 240    No 4-room  13.8 100.0    18.10    20.2   34.77
## 241 241    No 4-room  13.8 100.0    18.10    20.2   37.97
## 242 242    No 7-room  15.0  97.9    18.10    20.2   13.44
## 243 243    No 7-room  13.9  93.3    18.10    20.2   23.24
## 244 244    No 7-room  13.3  98.8    18.10    20.2   21.24
## 245 245    No 6-room  13.1  96.2    18.10    20.2   23.69
## 246 246    No 6-room  10.2 100.0    18.10    20.2   21.78
## 247 247    No 7-room  10.4  91.9    18.10    20.2   17.21
## 248 248    No 7-room  10.9  99.1    18.10    20.2   21.08
## 249 249    No 6-room  11.3 100.0    18.10    20.2   23.60
## 250 250    No 6-room  12.3 100.0    18.10    20.2   24.56
## 251 251    No 4-room   8.8  91.2    18.10    20.2   30.63
## 252 252    No 5-room   7.2  98.1    18.10    20.2   30.81
## 253 253    No 4-room  10.5 100.0    18.10    20.2   28.28
## 254 254    No 5-room   7.4  89.5    18.10    20.2   31.99
## 255 255    No 4-room  10.2 100.0    18.10    20.2   30.62
## 256 256    No 5-room  11.5  98.9    18.10    20.2   20.85
## 257 257    No 6-room  15.1  97.0    18.10    20.2   17.11
## 258 258    No 6-room  23.2  82.5    18.10    20.2   18.76
## 259 259    No 5-room   9.7  97.0    18.10    20.2   25.68
## 260 260    No 6-room  13.8  92.6    18.10    20.2   15.17
## 261 261    No 6-room  12.7  94.7    18.10    20.2   16.35
## 262 262    No 6-room  13.1  98.8    18.10    20.2   17.12
## 263 263    No 6-room  12.5  96.0    18.10    20.2   19.37
## 264 264    No 6-room   8.5  98.9    18.10    20.2   19.92
## 265 265    No 5-room   5.0 100.0    18.10    20.2   30.59
## 266 266    No 6-room   6.3  77.8    18.10    20.2   29.97
## 267 267    No 6-room   5.6 100.0    18.10    20.2   26.77
## 268 268    No 6-room   7.2 100.0    18.10    20.2   20.32
## 269 269    No 6-room  12.1 100.0    18.10    20.2   20.31
## 270 270    No 5-room   8.3  96.0    18.10    20.2   19.77
## 271 271    No 6-room   8.5  85.4    18.10    20.2   27.38
## 272 272    No 6-room   5.0 100.0    18.10    20.2   22.98
## 273 273    No 4-room  11.9 100.0    18.10    20.2   23.34
## 274 274    No 6-room  27.9 100.0    18.10    20.2   12.13
## 275 275    No 6-room  17.2  97.9    18.10    20.2   26.40
## 276 276    No 7-room  27.5 100.0    18.10    20.2   19.78
## 277 277    No 6-room  15.0 100.0    18.10    20.2   10.11
## 278 278    No 7-room  17.2 100.0    18.10    20.2   21.22
## 279 279    No 4-room  17.9 100.0    18.10    20.2   34.37
## 280 280    No 5-room  16.3 100.0    18.10    20.2   20.08
## 281 281    No 4-room   7.0 100.0    18.10    20.2   36.98
## 282 282    No 6-room   7.2 100.0    18.10    20.2   29.05
## 283 283    No 7-room   7.5  90.8    18.10    20.2   25.79
## 284 284    No 5-room  10.4  89.1    18.10    20.2   26.64
## 285 285    No 6-room   8.8 100.0    18.10    20.2   20.62
## 286 286    No 7-room   8.4  76.5    18.10    20.2   22.74
## 287 287    No 6-room  16.7 100.0    18.10    20.2   15.02
## 288 288    No 6-room  14.2  95.3    18.10    20.2   15.70
## 289 289    No 6-room  20.8  87.6    18.10    20.2   14.10
## 290 290    No 6-room  13.4  85.1    18.10    20.2   23.29
## 291 291    No 6-room  11.7  70.6    18.10    20.2   17.16
## 292 292    No 6-room   8.3  95.4    18.10    20.2   24.39
## 293 293    No 6-room  10.2  59.7    18.10    20.2   15.69
## 294 294    No 6-room  10.9  78.7    18.10    20.2   14.52
## 295 295    No 6-room  11.0  78.1    18.10    20.2   21.52
## 296 296    No 6-room   9.5  95.6    18.10    20.2   24.08
## 297 297    No 6-room  14.5  86.1    18.10    20.2   17.64
## 298 298    No 7-room  14.1  94.3    18.10    20.2   19.69
## 299 299    No 6-room  16.1  74.8    18.10    20.2   12.03
## 300 300    No 6-room  14.3  87.9    18.10    20.2   16.22
## 301 301    No 6-room  11.7  95.0    18.10    20.2   15.17
## 302 302    No 7-room  13.4  94.6    18.10    20.2   23.27
## 303 303    No 6-room   9.6  93.3    18.10    20.2   18.05
## 304 304    No 6-room   8.7 100.0    18.10    20.2   26.45
## 305 305    No 6-room   8.4  87.9    18.10    20.2   34.02
## 306 306    No 6-room  12.8  93.9    18.10    20.2   22.88
## 307 307    No 6-room  10.5  92.4    18.10    20.2   22.11
## 308 308    No 6-room  17.1  97.2    18.10    20.2   19.52
## 309 309    No 6-room  18.4 100.0    18.10    20.2   16.59
## 310 310    No 6-room  15.4 100.0    18.10    20.2   18.85
## 311 311    No 6-room  10.8  96.6    18.10    20.2   23.79
## 312 312    No 6-room  11.8  94.8    18.10    20.2   23.98
## 313 313    No 6-room  14.9  96.4    18.10    20.2   17.79
## 314 314    No 6-room  12.6  96.6    18.10    20.2   16.44
## 315 315    No 6-room  14.1  98.7    18.10    20.2   18.13
## 316 316    No 6-room  13.0  98.3    18.10    20.2   19.31
## 317 317    No 7-room  13.4  92.6    18.10    20.2   17.44
## 318 318    No 7-room  15.2  98.2    18.10    20.2   17.73
## 319 319    No 6-room  16.1  91.8    18.10    20.2   17.27
## 320 320    No 7-room  17.8  99.3    18.10    20.2   16.74
## 321 321    No 7-room  14.9  94.1    18.10    20.2   18.71
## 322 322    No 7-room  14.1  86.5    18.10    20.2   18.13
## 323 323    No 6-room  12.7  87.9    18.10    20.2   19.01
## 324 324    No 6-room  13.5  80.3    18.10    20.2   16.94
## 325 325    No 6-room  14.9  83.7    18.10    20.2   16.23
## 326 326    No 6-room  20.0  84.4    18.10    20.2   14.70
## 327 327    No 7-room  16.4  90.0    18.10    20.2   16.42
## 328 328    No 6-room  17.7  88.4    18.10    20.2   14.65
## 329 329    No 6-room  19.5  83.0    18.10    20.2   13.99
## 330 330    No 7-room  20.2  89.9    18.10    20.2   10.29
## 331 331    No 6-room  21.4  65.4    18.10    20.2   13.22
## 332 332    No 6-room  19.9  48.2    18.10    20.2   14.13
## 333 333    No 6-room  19.0  84.7    18.10    20.2   17.15
## 334 334    No 6-room  19.1  94.5    18.10    20.2   21.32
## 335 335    No 6-room  19.1  71.0    18.10    20.2   18.13
## 336 336    No 6-room  20.1  56.7    18.10    20.2   14.76
## 337 337    No 6-room  19.9  84.0    18.10    20.2   16.29
## 338 338    No 6-room  19.6  90.7    18.10    20.2   12.87
## 339 339    No 6-room  23.2  75.0    18.10    20.2   14.36
## 340 340    No 7-room  29.8  67.6    18.10    20.2   11.66
## 341 341    No 5-room  13.8  95.4    18.10    20.2   18.14
## 342 342    No 6-room  13.3  97.4    18.10    20.2   24.10
## 343 343    No 6-room  16.7  93.6    18.10    20.2   18.68
## 344 344    No 5-room  12.0  97.3    18.10    20.2   24.91
## 345 345    No 6-room  14.6  96.7    18.10    20.2   18.03
## 346 346    No 6-room  21.4  88.0    18.10    20.2   13.11
## 347 347    No 6-room  23.0  64.7    18.10    20.2   10.74
## 348 348    No 7-room  23.7  74.9    18.10    20.2    7.74
## 349 349    No 7-room  25.0  77.0    18.10    20.2    7.01
## 350 350    No 6-room  21.8  40.3    18.10    20.2   10.42
## 351 351    No 6-room  20.6  41.9    18.10    20.2   13.34
## 352 352    No 6-room  21.2  51.9    18.10    20.2   10.58
## 353 353    No 6-room  19.1  79.8    18.10    20.2   14.98
## 354 354    No 6-room  20.6  53.2    18.10    20.2   11.45
## 355 355    No 5-room  15.2  92.7    27.74    20.1   18.06
## 356 356    No 5-room   7.0  98.3    27.74    20.1   23.97
## 357 357    No 5-room   8.1  98.0    27.74    20.1   29.68
## 358 358    No 6-room  13.6  98.8    27.74    20.1   18.07
## 359 359    No 6-room  20.1  83.5    27.74    20.1   13.35
## 360 360    No 6-room  21.8  54.0     9.69    19.2   12.01
## 361 361    No 6-room  24.5  42.6     9.69    19.2   13.59
## 362 362    No 6-room  23.1  28.8     9.69    19.2   17.60
## 363 363    No 5-room  19.7  72.9     9.69    19.2   21.14
## 364 364    No 6-room  18.3  70.6     9.69    19.2   14.10
## 365 365    No 6-room  21.2  65.3     9.69    19.2   12.92
## 366 366    No 6-room  17.5  73.5     9.69    19.2   15.10
## 367 367    No 6-room  16.8  79.7     9.69    19.2   14.33
## 368 368    No 7-room  22.4  69.1    11.93    21.0    9.67
## 369 369    No 6-room  20.6  76.7    11.93    21.0    9.08
## 370 370    No 7-room  23.9  91.0    11.93    21.0    5.64
## 371 371    No 7-room  22.0  89.3    11.93    21.0    6.48
## 372 372    No 6-room  11.9  80.8    11.93    21.0    7.88

Number of variables and variable names

dim(housing_prices)
## [1] 372   8
names(housing_prices)
## [1] "ID"       "river"    "rooms"    "price"    "age"      "industry" "ptratio" 
## [8] "low_ses"

Present the study design, null and alternative hypotheses (5%)

Study Design: The cross-sectional investigation of 372 suburbs to determine whether there was variation in housing prices based on the number of rooms in houses.

Null Hypothesis (H0): There is no significant difference in median housing prices among houses with different numbers of rooms. Alternative Hypothesis (Ha): Median housing prices vary significantly among houses with different numbers of rooms.

Describe the characteristics of the study sample by the number of rooms/house (10%)

library(table1)
## 
## Attaching package: 'table1'
## The following objects are masked from 'package:base':
## 
##     units, units<-
table1(~ price + river + age + industry + ptratio + low_ses | rooms, data = housing_prices)
4-room
(N=15)
5-room
(N=27)
6-room
(N=254)
7-room
(N=76)
Overall
(N=372)
price
Mean (SD) 17.3 (10.7) 14.0 (5.05) 18.9 (5.50) 28.8 (11.7) 20.5 (8.59)
Median [Min, Max] 13.8 [7.00, 50.0] 14.4 [5.00, 23.7] 19.4 [5.00, 50.0] 27.5 [7.50, 50.0] 19.8 [5.00, 50.0]
river
No 15 (100%) 23 (85.2%) 239 (94.1%) 67 (88.2%) 344 (92.5%)
Yes 0 (0%) 4 (14.8%) 15 (5.9%) 9 (11.8%) 28 (7.5%)
age
Mean (SD) 93.5 (15.9) 89.8 (20.4) 75.6 (24.3) 77.2 (21.1) 77.7 (23.6)
Median [Min, Max] 100 [37.8, 100] 96.2 [9.80, 100] 84.5 [6.00, 100] 82.7 [2.90, 100] 87.3 [2.90, 100]
industry
Mean (SD) 17.8 (2.23) 17.7 (5.43) 13.6 (6.16) 11.1 (6.53) 13.5 (6.32)
Median [Min, Max] 18.1 [9.90, 19.6] 18.1 [6.91, 27.7] 13.9 [2.18, 27.7] 9.90 [1.89, 19.6] 18.1 [1.89, 27.7]
ptratio
Mean (SD) 19.3 (1.94) 18.7 (2.31) 19.3 (1.71) 18.4 (1.81) 19.1 (1.82)
Median [Min, Max] 20.2 [14.7, 20.2] 20.1 [14.7, 21.2] 20.2 [14.7, 21.2] 18.0 [14.7, 21.0] 20.2 [14.7, 21.2]
low_ses
Mean (SD) 24.4 (11.4) 23.3 (6.75) 14.5 (5.37) 9.14 (6.25) 14.4 (7.15)
Median [Min, Max] 29.3 [3.26, 38.0] 24.0 [10.2, 34.4] 14.1 [5.08, 34.0] 6.79 [1.73, 25.8] 13.6 [1.73, 38.0]

Develop and interpret a histogram for the distribution of house prices (10%)

library(ggplot2)
library(grid)
library(gridExtra) 
library(dplyr)
## 
## Attaching package: 'dplyr'
## The following object is masked from 'package:gridExtra':
## 
##     combine
## The following objects are masked from 'package:stats':
## 
##     filter, lag
## The following objects are masked from 'package:base':
## 
##     intersect, setdiff, setequal, union
library(GGally)
## Registered S3 method overwritten by 'GGally':
##   method from   
##   +.gg   ggplot2
library(ggthemes)

p = ggplot(data = housing_prices, aes(x = price)) + geom_histogram(color = "black", fill = "light blue") + labs(x = "Median housing prices (x USD 1,000)") + labs(y = "Count number")

p1 = ggplot(data = housing_prices, aes(x = price, y = ..density..)) + geom_histogram(color = "black", fill = "light blue") +  geom_density(col="red") + labs(x = "Median housing prices (x USD 1,000)") + labs(y = "Density")

grid.arrange(p, p1, nrow = 1.5, top = textGrob("Distribution of house prices", gp = gpar(fontsize = 18, font = 2)))
## `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.
## Warning: The dot-dot notation (`..density..`) was deprecated in ggplot2 3.4.0.
## ℹ Please use `after_stat(density)` instead.
## This warning is displayed once every 8 hours.
## Call `lifecycle::last_lifecycle_warnings()` to see where this warning was
## generated.
## `stat_bin()` using `bins = 30`. Pick better value with `binwidth`.

Develop and interpret a box plot to describe the differences in housing prices among the number of rooms per household (10%)

p = ggplot(data = housing_prices, aes(x = rooms, y = price, fill = rooms, col = rooms))

p1 = p + geom_boxplot(col = "black") + geom_jitter(alpha = 0.01) + labs(x = "Room numbers of each household", y = "Median housing prices (x USD 1,000)") + ggtitle("Box Plot of housing prices by room numbers of each household") + theme_bw()

p1

Conduct a statistical test to determine whether housing prices were different among houses with different numbers of rooms. Interpret the findings (15%)

Kruskal-Wallis test

kruskal.test(price ~ rooms, data = housing_prices)
## 
##  Kruskal-Wallis rank sum test
## 
## data:  price by rooms
## Kruskal-Wallis chi-squared = 75.504, df = 3, p-value = 2.826e-16

ANOVA test

anova_test= aov(price ~ rooms, data = housing_prices)
summary(anova_test)
##              Df Sum Sq Mean Sq F value Pr(>F)    
## rooms         3   7162  2387.2   43.49 <2e-16 ***
## Residuals   368  20202    54.9                   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

The Kruskal-Wallis and ANOVA tests given p-value of approximately zero (2.826e-16 and 2e-16), P-value < 0.05. Therefore, null hypothesis (H0) in favor of the alternative hypothesis (Ha) is rejected.

In conclusion, there are significant differences in housing prices among houses with different numbers of rooms.

Determine which particular number of rooms/house had different house prices using the Tukey posthoc test. Fill in the following table and interpret the findings (20%)

tukey_result = TukeyHSD(anova_test)
tukey_result
##   Tukey multiple comparisons of means
##     95% family-wise confidence level
## 
## Fit: aov(formula = price ~ rooms, data = housing_prices)
## 
## $rooms
##                    diff       lwr       upr     p adj
## 5-room-4-room -3.215556 -9.373321  2.942210 0.5331459
## 6-room-4-room  1.603780 -3.477109  6.684668 0.8475492
## 7-room-4-room 11.511053  6.108559 16.913546 0.0000004
## 6-room-5-room  4.819335  0.948716  8.689954 0.0077590
## 7-room-5-room 14.726608 10.442544 19.010672 0.0000000
## 7-room-6-room  9.907273  7.407162 12.407384 0.0000000
tukey_results <- data.frame(
  
  Comparisons = c("5-room houses vs. 4-room houses","6-room houses vs. 4-room houses", "7-room houses vs. 4-room houses", "6-room houses vs. 5-room houses", "7-room houses vs. 5-room houses", "7-room houses vs. 6-room houses"),
  
  Mean_Differences_in_housing_price= c("-3.21 (-9.37, 2.94)","1.60 [-3.48, 6.68]","11.51 [6.11, 16.91]","4.82 [0.95, 8.69]","14.73 [10.44, 19.01]","9.91 [7.41, 12.41]"),
  
  P_Value = c("0.5331", "0.8475", "0.0000", "0.0078", "0.0000", "0.0000")
)

print(tukey_results, row.names = FALSE)
##                      Comparisons Mean_Differences_in_housing_price P_Value
##  5-room houses vs. 4-room houses               -3.21 (-9.37, 2.94)  0.5331
##  6-room houses vs. 4-room houses                1.60 [-3.48, 6.68]  0.8475
##  7-room houses vs. 4-room houses               11.51 [6.11, 16.91]  0.0000
##  6-room houses vs. 5-room houses                 4.82 [0.95, 8.69]  0.0078
##  7-room houses vs. 5-room houses              14.73 [10.44, 19.01]  0.0000
##  7-room houses vs. 6-room houses                9.91 [7.41, 12.41]  0.0000

The Tukey posthoc test shows that houses with 7 rooms had significant differencess in housing price (P-value ≈ 0 <0.05) compared to the ones of 4, 5 and 6 rooms. Similar manner is found when comparing houses with 6 rooms to those with 5 rooms (P-value = 0.0078 <0.05).

On the contrary, in case of comparing the houses with 5 and 6 rooms to the house with 5 rooms, there are no statistically significant differences in house prices (P-value=0.53 and 0.85 > 0.05).